Data band identification for tape servo system using multiple servo bands

ABSTRACT

A magnetic tape and servo elements of a magnetic head for reading and writing to the magnetic tape can ascertain servo band signals from different servo bands that are vertically aligned and adjacent to one another. When operating in a write or read mode, at least two servo elements can be activated to respond to a write/read operation based on a determined position across a width of the servo bands in the magnetic tape. The determined position is based on various pattern combinations from different servo band identifiers from the servo band signals.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/669,735 filed May 10, 2018, entitled “DATA BAND IDENTIFICATION FORTAPE SERVO SYSTEM USING MULTIPLE SERVO BANDS”, the contents of which areherein incorporated by reference in their entirety.

FIELD

The present disclosure relates to tape servo systems, and moreparticularly data band identification using multiple servo bands.

BACKGROUND

Servo signals are recorded on servo bands that are next to data tracksformed along a longitudinal direction of magnetic tape. A magnetic headrecords or reads a data track based on which servo band along the tapewidth the head is positioned. Linear Tape-Open (LTO) tape format has 4data bands isolated on each side by individual servo bands, so for 4data bands there is a total of 5 servo bands. Each data band is uniquelyidentifiable by using servo band information. Servo bands are timingsignals based on chevron stripes, which carry both tracking positionerror signal (PES) and encoded data information that identifies tapeposition, manufacturing information and servo or data bandidentification information.

In LTO 1 through 6 standard generations, data bands are uniquelyidentified by detecting the longitudinal offset that existed between thetwo servo bands on either side of each data band. Thus, both servo bandinformation is used by a defined relationship using a longitudinaloffset dimension to detect which data band the magnetic head was locatedat. The longitudinal physical dimensional shift uniquely identifies eachdata band by measuring each of servo band information/data together.

In LTO 7 standard, the format changed to use each servo band toindividually identify the data bands by encoding unique identifiers aspart of the servo format longitudinal position information (LPOS) byusing frame encoding techniques with pulse position modulation to encodeinformation. This allowed servo bands to be aligned vertically which isan improved manufacturing process and provides higher servo framesampling capability for higher track densities. However, this new formatalso enabled only a single servo head to be active to determine whereone is located, whereas the previous method required both to be readsimultaneously to determine the data band positions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a tape servo device or systemaccording to various aspects (embodiments) described.

FIG. 2 is an example diagram illustrating another tape servo device orsystem according to various aspects described.

FIG. 3 is an example diagram illustrating another tape servo device orsystem according to various aspects described.

FIG. 4 is an example diagram illustrating another tape servo device orsystem according to various aspects described.

FIG. 5 is an example process flow for tape servo device or systemdevices to identify position along a magnetic tape in accordance withvarious aspects described.

FIG. 6 is a block diagram representing exemplary non-limiting networkedenvironments in which various non-limiting embodiments described hereincan be implemented.

DETAILED DESCRIPTION

The present disclosure will now be described with reference to theattached drawing figures, wherein like reference numerals are used torefer to like elements throughout, and wherein the illustratedstructures and devices are not necessarily drawn to scale. As utilizedherein, terms “component,” “system,” “interface,” and the like areintended to refer to a computer-related entity, hardware, software(e.g., in execution), and/or firmware. For example, a component can be aprocessor (e.g., a microprocessor, a controller, or other processingdevice), a process running on a processor, a controller, an object, anexecutable, a program, a storage device, a computer, a tablet PC and/ora user equipment (UE) (e.g., mobile/wireless phone, etc.) with aprocessing device. By way of illustration, an application running on aserver and the server can also be a component. One or more componentscan reside within a process, and a component can be localized on onecomputer and/or distributed between two or more computers. A set ofelements or a set of other components can be described herein, in whichthe term “set” can be interpreted as “one or more.”

Further, these components can execute from various computer readablestorage media having various data structures stored thereon such as witha module, for example. The components can communicate via local and/orremote processes such as in accordance with a signal having one or moredata packets (e.g., data from one component interacting with anothercomponent in a local system, distributed system, and/or across anetwork, such as, the Internet, a local area network, a wide areanetwork, or similar network with other systems via the signal).

As another example, a component can be an apparatus with specificfunctionality provided by mechanical parts operated by electric orelectronic circuitry, in which the electric or electronic circuitry canbe operated by a software application or a firmware application executedby one or more processors. The one or more processors can be internal orexternal to the apparatus and can execute at least a part of thesoftware or firmware application. As yet another example, a componentcan be an apparatus that provides specific functionality throughelectronic components without mechanical parts; the electroniccomponents can include one or more processors therein to executesoftware and/or firmware that confer(s), at least in part, thefunctionality of the electronic components.

Use of the word exemplary is intended to present concepts in a concretefashion. As used in this application, the term “or” is intended to meanan inclusive “or” rather than an exclusive “or”. That is, unlessspecified otherwise, or clear from context, “X employs A or B” isintended to mean any of the natural inclusive permutations. That is, ifX employs A; X employs B; or X employs both A and B, then “X employs Aor B” is satisfied under any of the foregoing instances. In addition,the articles “a” and “an” as used in this application and the appendedclaims should generally be construed to mean “one or more” unlessspecified otherwise or clear from context to be directed to a singularform. Furthermore, to the extent that the terms “including”, “includes”,“having”, “has”, “with”, or variants thereof are used in either thedetailed description and the claims, such terms are intended to beinclusive in a manner similar to the term “comprising.”

In consideration of described deficiencies of only a single servo headbeing read, the use of both can be advantageous for writing operationsas potential advantages exists for eliminating write errors orascertaining location along magnetic tape width, especially whenover-writing existing data by reading a single head. In particular,improved accuracy and lower error can be obtained by concurrently,simultaneously, or at about the same time reading two servo bands withdifferent servo elements in write mode of operation. In particular, bothservo band information can be acquired by a defined relationship using alongitudinal offset dimension to detect which data band the magnetichead is located at.

Embodiments described herein combine different method techniques,eliminating undesirable features of past formats yet maintain thebeneficial features of each format. Embodiments further includeadditional aspects such as using the actual location of the physicalservo heads to assist with the data band identification process.Embodiments further improve on conventional approaches by eliminatingundesirable properties and behavior. Embodiments eliminate the physicallongitudinal shift as used in original format (LTO 1 to 6). Embodimentsalso eliminate the use of single reader (or servo element—servo readeror servo writer) to know where the heads are located during thewrite/read mode (e.g., when the magnetic tape is being written new datato a data band or over-writing old data with new data, or reading dataout from the tape). Embodiments further provide that the data bandidentification is done by both servo bands being read concurrently orsimultaneously with respect to one another.

Embodiments further provide that all servo bands are vertically alignedand are without any substantial shift with respect to each adjacentservo band. Embodiments use LPOS servo frame encoding to encode anddecode data band identification. Embodiments further provide that thedata band ID decoding acquires the knowledge of which servo heads arereading which servo tracks (of a servo band) to determine (or identify)the data bands from one another.

Additional aspects and details of the disclosure further described belowwith reference to figures

FIG. 1 illustrates an example computing device or system that exampleoperations, systems, apparatus, or methods described herein, andequivalents, can be processed or operate as a tape servo device orsystem. The example computing device/system 100 can be a servo devicethat includes a processor 102, a memory 104, magnetic head device(s) 106and input/output ports 110 operably connected by an input/output (I/O)interface or an external/internal bus 108. The computer device 100 caninclude communication or processing circuitry as circuit(s) 130configured to facilitate providing data or processing working sets ofapplication data to adaptively read or write a magnetic tape 116 via oneor more servo readers 112 or servo writers 114, which can also bereferred to as servo read heads or servo write heads that have signalprocessing circuitry (e.g., coils or the like) to read or write datawith the magnetic tape 116.

In different examples, circuit 130 can be implemented in hardware,software, firmware, or combinations thereof. While circuit 130 isillustrated as a hardware component attached to the bus 108, it is to beappreciated that in one example, circuit 130 could be implemented in theprocessor 102, such as a system on a chip (SoC), single integrated chip,microcontroller or the like. In an example configuration of the computer100, the processor 102 can be a variety of various processors includingdual microprocessor, controller, or other single/multi-processorarchitectures. A memory 104 can include volatile memory and/ornon-volatile memory. Non-volatile memory can include, for example, ROM,PROM, or other memory. Volatile memory can include, for example, RAM,SRAM, DRAM, or other memory.

The I/O interface/bus 108 can be a single internal bus interconnectarchitecture and/or other bus or mesh architectures. While a single busis illustrated, it is to be appreciated that the computer 100 cancommunicate with various devices, logics, and peripherals using otherbusses (e.g., PCIE, 1394, USB, Ethernet). The bus 108 can be typesincluding, for example, a memory bus, a memory controller, a peripheralbus, an external bus, a crossbar switch, a local bus, orexternal/internal interface.

The magnetic tape 116 comprises a plurality of servo bands (e.g., Servobands 0 thru 4, referenced 120-128) with a plurality of data bands(e.g., Data bands 0 thru 3, references 130-136). As can be seen the tapeis forwarded from a beginning of tape (BOT) to an end of tape (EOT)moving in the direction of the arrow from a right to a left direction asillustrated, for example.

As the LTO standards specify, multiple servo locations can be definedwithin each servo band (e.g., 120-128). These servo locations can beused for track following while the cartridge is being operated in acartridge drive (not shown). The servo bands (e.g., 120-128) can bewritten prior to the cartridge being usable for data storage andretrieval. All servo locations can be located at specific distances fromthe Tape Reference Edge, which is the bottom edge of the tape. Eachservo band (e.g., 120-128) can contain servo frames consisting of servostripes (e.g., chevron stripes, or the like). Servo frames can beencoded as Longitudinal position POS words to provide longitudinalposition down the length of the tape (e.g., from BOT to EOT). All servobands (e.g., 120-128) line up relative to each other across the tape andspecial fields can identify the servo bands. Here, the servo bands(e.g., 120-128) are offset from one another by which ratio metric datarelated to the offsets can be used to determine a position of the magnethead or a servo element (e.g., one or more: servo reader(s) 112 or servowriter(s) 114, as servo read and write elements). Data tracks of Databands (e.g., 130-136) that can be read from or written to can be locatedbetween pairs of servo bands (e.g., 120-128).

As observed from FIG. 1 above, the longitudinal physical dimensionalshift can uniquely identify each data band by measuring the each servoband information together. Table 1 below shows how these shifts are usedto decode where the magnetics heads are at.

TABLE 1 Servo Band Servo Band n n + 1 Relative position of n + 1 servo 01 Late by 33.33 μm ± 4.16 μm 1 2 Early by 33.33 μm ± 4.16 μm 2 3 Late by66.67 μm ± 4.16 μm 3 4 Early by 66.67 μm ± 4.16 μm

This format can be modified to use each servo band to individuallyidentify the data bands by encoding unique identifies as part of theservo format longitudinal position information LPOS by using frameencoding technique which uses pulse position modulation to encodeinformation. This allowed servo bands to be aligned vertically which isan improved manufacturing process and provides higher servo framesampling capability for higher track densities.

However, this new format also enabled only single servo head to beactive to determine where one is whereas the previous method requiredboth be read simultaneously to determine the data band positions. Theuse of both as a hard requirement can be advantages for writing sincepotential over writing existing data by reading single head is more thanthe requirement of simultaneously reading two servo bands.

Embodiments described herein combine at least two methods, eliminatingundesirable features of both of different formats yet maintaining thebeneficial features of each. Embodiments further add additional aspectssuch as the actual location of the physical servo heads to assist withthe data band/track identification process. Embodiments improve onconventional approaches by eliminating undesirable properties andbehavior. Embodiments eliminate the physical longitudinal shift as usedin original format (LTO1-6). Embodiments eliminate the use of singlereader to know where are the heads during the write or read mode ofoperation so data can be accurately written to, over-written or readfrom the magnetic tape. Embodiments provide that the data bandidentification is done by both servo bands being read simultaneously.Embodiments provide that all servo bands are vertically aligned.Embodiments use LPOS servo frame encoding to encode and decode data bandidentification. Embodiments further provide that the data band IDdecoding uses the knowledge of which servo heads are reading which servotracks of servo bands to determine the data bands.

Referring to FIG. 2, illustrates other aspects of the tape servo device100 for determining a position or data band identification for a tapemagnetic head. The magnetic tape 216 can be similar to the magnetic tape116, but differ in aspects. For example, servo bands (e.g., 220-228)comprise chevron stripes or frames 204 that can provide timinginformation or timing. Four sets of these stripes (e.g., 18 stripes withfour different sets comprising five stripes, five stripes, four stripesand four stripes at each set) can form a servo frame 204 along thelongitudinal direction of the magnetic tape 216. Each servo frame 204,for example, can be encoded with a one or zero, for example, accordingto different patterns repeating continuously, which can bedifferentiated based on variances of the stripes with one or more setsof strips. Each servo band 220-228 can comprise a continuous line ofservo frames that can repeat in pattern or vary depending on a ratio ofthe stripes therein with respect to a stripe set/groupcentre-line/point, or other stripes, for example.

In an aspect, the magnetic tape 216 comprises servo bands (e.g.,220-228) that are vertically aligned at an alignment 202 along themagnetic tape. As such, at each servo frame 204 the servo bands (e.g.,220-228) are vertically aligned with one another across a width of themagnetic tape, the width spanning from an edge of a tape edge guard bandto another tape edge guard band at a tape reference edge 206, forexample.

A servo element (e.g., SR 112 or SW 114) can move up and down along avertical direction over the servo bands (e.g., 220-228). For example,one or more servo elements can move up, read a timing or moves down andread another timing depending on the position along the tape, eithervertically or longitudinally at a Longitudinal Position (LPOS)transverse along the tape direction. For example, a servo element can bethe servo reader 112 or a dedicated servo reader that reads a particulartiming by detecting pulses similar in manner to a disk, for example. Theprocessor 102 or controller of the magnetic head 106 can be configuredto perform an LPOS method of operation for analyzing and providing dataassociated with the tape 216. LPOS method(s) for example can bereferring to as a differential pulse position modulation, which can be aset of LPOS processes that are related to, or associated with,pulse-position modulation. Pulse-position modulation (PPM) is a signalmodulation that can be used for analog and digital signal transmissionswhere data is being transmitted with short pulses. These short pulsescan have the same or similar width and amplitude, in which the parameterthat changes is a delay between each pulse. Differential pulse positionmodulation can be used for performing LPOS methods for determining alocation of data along a longitudinal position of the tape 216, forexample, or along the forward/tape motion of the tape. Differentialpulse position modulation (or D-PPM) can transmit data independently ofa clock, with or without a clock. Rather than the delay between pulsestaking a reference from the rising edge of a clock, each delay can takereference from the falling edge of the previous pulse, for example.Thus, D-PPM can encode a signal regardless of a clock, and the length ofthe encoded signal is not necessarily fixed, but can be for one or morebytes, for example. D-PPM can thus be a part of any LPOS methodperformed as a part of the processor 102 or other controller processesherein, for example.

The processor 102 or controller can thus analyze peaks of read pulses toknow which pulse the servo element 112, 114 went through. The servoelement can count these peaks based on a dimension or timing betweenazimuth points (e.g., referred to as an A-B (AB) distance, a fixeddistance or half an AC distance of a servo frame) between sets ofstripes within a servo frame. By noting the different distances (e.g.,AB, AC, azimuth angle, points between peaks, or other related ratiometric data/measurements of peaks or the tape), in particular, thecontroller 102, or magnetic head 106 can know where the head or tape ispositioned or located. This position or location can include thespecific data band based on pattern combinations from at least twoactivated servo elements (e.g., 112, 114), as well as the data tracklocation from among different data tracks of a data band (e.g.,230-236).

In particular, additional bursts can also be used to accommodate for thetape speed not being completely accurate, but having variation, and takeinto account more than only relying on timing alone, as variation in thespeed of the magnetic tape, for example, can cause inaccuracy. For thisreason, ratio metric measurements can also be used regardless of thespeed variation such that if the head 106 is at portion of the tape(e.g., a top, a middle or a bottom), the points in between become fixeddistances by taking into account certain ratio metrics that eliminate aspeed variation variable. For example, if in the middle of the magnetictape 216, dividing by the timing could get a ratio of 0.5 based ondistances within the peaks or bursts of the sensor band to accuratedetermine a location: a particular data band, a particular data trackwithin a data band, an order of one or more vertical positions along thetape, data bands or data tracks, or other similar position information,for example.

In an aspect, at least two servo elements can be activated in order todetermine accurately a vertical position or a location from among theservo bands 220-228, data bands 230-236 between different servo bandpairs, and the data tracks of the data bands. For example, between servoband zero 220 and servo band one 222, the head 106 can have multipleservo elements as readers 112/writers 114 that are writing and readingbased on where the head 106 is relative to those servo bands (e.g., bandzero and one). The position of the magnetic head 106 can be determinedby the activation of at least two servo elements. In this manner, anytransverse changes can be compensated for and further averages can bemade for greater accuracy as an advantage over just a single elementoperating to read from a position in a read mode of operation (wheredata is being processed or rendered in a read operation). Rather thanusing one servo element, two can be used, for example, for better signalquality by averaging the noise and the dimensional changes in lateraltape changes or changes away from a tape path direction. A bottom servoelement can be on the bottom servo band (e.g., servo band one 222) andthe top servo element be on the top servo band (e.g., servo band zero220), or any other combination on any of the five bands for determiningwhich data band (e.g., Data band 3 236) the magnetic head is at andwhich data track that is being written to, for example, in a write modeof operation, or read therefrom in a read mode of operation.

The magnetic head 106 can operate in a write mode and a read mode. Themagnetic head can operate to activate two servo elements for readingservo band patterns, pattern combinations, or codewords formed from apattern combination such as in a write and read mode to furtherdetermine a location or a vertical position of the head 106 from amongthe servo bands 220-228, data bands 230-236, and data tracks therein(e.g., about 52 or other plurality at each data band). As such, inresponse to a write/read operation as a write process to overwrite/writedata to/read data from one or more data bands 230-236, the magnetic head106 can activate more than one servo element for obtaining positioninformation and further ensuring a vertical position or the particulardata band/track to be written at or read from.

In one example, the servo bands 220-228 can each comprise data for aservo band signal to be read by the servo elements. Each servo band cancomprise different servo band signals that have a unique identifier. Themagnetic head 106, processor 102, or other controller component cancombine the identifiers from two servo bands to determine a patterncombination or particular codeword that specifically and uniquelyidentifiers the data band location or data band ID between the pair ofservo bands with activated serve elements reading the servo bandsignals. The pattern combination or codeword combination is thencompared to a stored pattern combination or patterned codeword. If amatch occurs between the pattern combination and the stored patterncombination, then the particular data band (e.g., data band three 236,or otherwise) that is associated with the stored pattern combination orcodeword indicates the location or vertical position of the magnetichead 106 among the different servo bands 220-226 at the particular databand.

Referring to FIG. 3, illustrated is another example of the tape servodevice 100 for determining a position or data band identification for atape magnetic head. Here, two servo elements (two SRs, two SWs, or acombination thereof) can determine a servo signal along the sensor band(e.g., 320 and 322) in order to extract a servo band identifier (ID)provided continuously along the magnetic tape and substantially parallelto the other servo bands. Each servo band ID can be a unique identifierfrom among the servo bands of the tape as well as be repeated from amongservo frames and LPOS frames (e.g., 36 servo frames), substantially andvertically aligned with one another. The magnetic head 106 can thenanalyze the pattern combination or codeword formed from among two servobands and determine a position of the servo elements 112/114 at a databand, or a data track within a data band, from among the various databands and tracks on the tape, for example.

Determining the position can further include comparing the patterncombination/codeword formed from two servo band IDs with a correspondingpattern combination 342 stored in a memory (e.g., a memory 104, a memoryof the magnetic head 106 or other internal or external memory to thedevice). If a matching pattern combination is found, then an associatedlocation or position information can be determined based on that whichis associated in the memory with the stored pattern 342.

In a write mode of operation or a write operation where data is beingwritten or overwritten at a particular location, a determination of theparticular exact location that writing will occur can be advantageousand prevent over-trimming or under-trimming data within the data tracksof a data band, for example. Likewise, ensuring a more precise locationfor reading data can also be advantageous; although one or more servoelements can be used for read operation(s), and at least two servoelements activated for write operation(s), for example. Further, byensuring at least two servo elements are activated for write operationthe magnetic head 106 is kept from writing to a wrong track, and knowingthe precise location along a vertical direction at all times, despitevariation in speed or uniform motion direction from mechanical variancesis valued for being more precise over time. Not only can the magnetichead 106 or a pair of two or more servo elements know which data band itis at or on, but also where the head is within micron/nano meters on thetape so as to not overwrite a pervious track, even if on the right band.If the magnetic head does not know the exact ratio location accurately,it could over-trim or not trim to a precise dimension at a track or atrack number/location 340 based on at least two actuated/activated servoelements (e.g., 112/114) in a write operation. These operations canotherwise become more difficult with greater and greater tape densitiesbeing generated on tapes.

In a read mode of operation, for example, both servo elements or atleast two, can be utilized if both are actuated or available for use, asin the write mode of operation. If only one servo head is available inthe read mode, however, the drive/processor/controller/magnetic head orother component of the device (e.g., 100 to 300) can still read datatracking on the single servo element and locating data bands using acounting servo method or counting each track, for example, by startingthe head at the top/bottom edge and moving down/up while detecting eachof the servo bands. These bands can thus be counted using feedback, forexample, as an actuator position that could come from a coarse steppermotor (not shown) as an actuator could have two motors (not shown), acoarse stepper to move up and down in small steps and a fine linear finemotor to track servo signals for example as a part of or integrated inthe circuitry 130.

In particular, the magnetic head 106 can operate to utilize a top andbottom servo element to compensate for Transverse Dimensional Stability(TDS) of the media or magnetic tape and keep from writing at a datatrack without trimming to a perfect dimension (e.g., being overlynarrow) and afterwards possibly not enable reading of the track, thusresulting in a hard read error, for example. In the read mode, only onehead could be used to know which data band the servo elements ormagnetic head are in, and is not as critical/disrupting to thedevice/system 100 if an error occurs, as such the magnetic head canactuate one servo element to determine position for a read operation,and two servo elements for reading the signals from the servo bands anddetermining a pattern combination/codeword for writing operation(s).

In an aspect, the pattern combination can be formed from servo band IDsextracted from unique servo band IDs or Unique Data Band IdentificationMethod (UDIMs) based on data from different servo bands extractedconcurrently or simultaneously with a pair of servo elements. Thelocation can be derived based on azimuth or ratio metric measurementsbased lateral information for tracking, as embedded ones and zeros withthe stripes patterns in a five stripe, five stripe, four stripe, fourstripe formation, and changes in distances between the stripes of anysubset of stripes therein or the stripes with respect to one another ina servo frame. This information can indicate a frame location (e.g., aservo frame location within an LPOS frame or the like), and can alsoprovide data band identification or a data band ID or a servo band ID.By combination different IDs from among servo bands to derive a patterncombination or codeword, the magnetic head can know precisely where itis located in a write/read operation to a data track for example. Byreferencing the pattern to an associated position, the magnetic head 106can determined an exact vertical location among any one or more databands.

In one aspect, during write mode, the device/systems can obtain an exactdata band position by writing into a data field a small metadata in eachdata set so even without the servo(s), the drive can search data fieldsand detect those repeating meta data in order to know which band it isin at any one time.

In aspect, each servo band 330-336, for example, can be identified bythe following code embedded in the LPOS using a servo frame encodingmethod. This identification can be demonstrated in the figure or tablebelow, as an example, where the ID encoded is not limited to anyparticular ID and can be numeric, alphabetic, alphanumeric or some othersymbol (mark) as an ID, or a combination thereof. As such, anycombination of IDs from a combination of different servo bands providesa unique or different pattern combination/codeword using at least twoactivated servo elements in contrast to only one servo element. Table 2is thus only one example and any variances of IDs or configurations ofdifferent IDs can be envisioned to ID a particular band in combinationwith other IDs of other bands, specifically in order, number ofcharacter, for example.

TABLE 2 ID encoded per UDIM Servo Band 0 3 Servo Band 1 3 Servo Band 2 0Servo Band 3 0 Servo Band 4 3

Use of servo head identification as top or bottom plus the UDIM code perservo band can be utilized by the device 100 (e.g., via the magnetichead or processor 102) to correctly identify the data bands where theread and write heads/servo elements are located. This is demonstratedfor example as shown below in Table 3. Thus, for example, a first servoelement at servo band 320 as a top servo element, and a second servoelement as a bottom or below servo element at servo band 322 can bematched up as a codeword or pattern combination to identify the locationat data band ID 3, and so on for each row of the table, for example.

TABLE 3 Data Band ID Top Servo Bot Servo 3 3 3 1 3 0 0 0 0 2 0 3

It is possible to detect which band the head(s) 106 is/are at by knowingthe actual servo head/element and the UDIM number for the pairs of servotracks (e.g., 320-328). This is demonstrated for example as shown intable 4 below per case.

TABLE 4 Data Data Data Data Case: UDIM Band 0 Band 1 Band 2 Band 3 TopServo Head 3 No Yes No Yes Top Servo Head 0 Yes No Yes No Bot Servo Head3 No No Yes Yes Bot Servo Head 0 Yes Yes No No

Therefore, reading single servo band is not necessarily possible ordesirable to detect which data band the heads are at unless both top andbottom servo heads are read with the knowledge of location of the servoheads as top or bottom.

Referring to FIG. 4, illustrated is an example magnetic heads with servoelements 402-408 located on the top and bottom on each servo band for awrite/read operation. The magnetic heads with two servo heads 402-408have two servo heads or elements activated on two different servo bands420-428, respectively. Although different servo band UDIM IDs arecontinuous along the magnetic tape 416, or are even the same withrespect to an adjacent servo band, the combination of each servo bandidentifier as a pattern combination is what can uniquely identify thelocation of the magnetic head with servo elements 402-408, as such nocombination of two identifiers is the same, or in the same order fromtop to bottom or bottom to top servo band, for example. Additionally,these particular servo band identifiers (e.g., 3 for servo band 420, 3for servo band 422, 0 for servo band 424, 0 for servo band 426, and 3for servo band 428) can be different than the given example by number,character, letter, symbol, asci, alpha-numeric, or the like, such thatno two combinations provide the same pattern combination or codeword byorder or sequence, or otherwise, for example.

During a write/read mode of operation, where the magnetic head iswriting data or overwriting existing data to a data band 430-436, or oneor more data tracks therein, then at least two servo heads/elements areactuated, turned on and operational for determining position accuracy. Amagnetic head (e.g., 106) has both servo band identifiers as a combinedpattern or codeword from vertically aligned servo band IDs, where oneposition, for example, is on data band 3 436, the top servo element ofservo elements 402 has a particular ID and bottom or servo band UDIM ID422 must have the identifier (e.g., 3) associated with.

In an embodiment, each servo band ID can comprise a bit pattern formingone or more bytes that repeats along the longitudinal direction of thetape, in which a pattern combination from among two servo band IDs isunique for each pair of servo bands. For example, an n-bit pattern, inwhich n is an integer of at least one (e.g., a four-bit pattern), orother number of bits as a byte can be configured at each servo band420-428 continuously along servo frames so that a current data band ortrack can be determined along a vertical position of the tape width. Theservo frame(s) for all the bands can start at a same longitudinallocation being vertically aligned within a tolerance (e.g., in micrometers, or other minute tolerance). For example, a byte binary servoband identifier field can provide the byte as the servo band identifierin the servo manufacturer word (SMW) or across servo frames of an LPOSword (e.g., about 36 servo frames).

While the methods or process flows are illustrated and described hereinas a series of acts or events, it will be appreciated that theillustrated ordering of such acts or events are not to be interpreted ina limiting sense. For example, some acts can occur in differentorders/concurrently with other acts or events apart from thoseillustrated/described herein. In addition, not all illustrated actscould be required to implement one or more aspects or embodiments of thedescription herein. Further, one or more of the acts depicted herein maybe carried out in one or more separate acts or phases.

Referring to FIG. 5, illustrated is an example process flow 500 foridentifying a position of a magnetic head on a magnetic tape. These actsor steps of the process flow 500 can apply to one or both read/writemodes of operation for reading data from a more precise, exact locationalong a width of the tape, writing data at the location or over-writingthere-at, for example. Write mode is only one example here forillustrated one or more particular aspects/embodiments herein. Themethod 500 can initiate at 502, with reading, via at least two servoband elements (e.g., 112/114) concurrently or simultaneously, differentservo band signals of servo bands that are vertically adjacent to oneanother and vertically aligned along the magnetic tape (e.g., 116 thru416) such as along a width from a top edge to a bottom edge or referenceedge (e.g., edge 206).

At 504, the process flow 500 includes deriving servo band identifiersassociated with the servo band signals that identify the plurality ofservo bands.

At 506, in response to performing a write/read operation, the magnetichead or associated processor (e.g., 102) can determine a patterncombination or an associated codeword of bits or byte(s) from among aplurality of pattern combinations based on the servo band identifiers.Each pattern combination or codeword can be unique to a pair of servobands along the width of the tape, for example.

At 508, in response to performing the write/read operation, determininga position of the magnetic head can be further determined among theplurality of servo bands based on the pattern combination.

In other aspects, the plurality of pattern combinations can comprise afirst pattern combination formed by a first servo band identifier of afirst servo band and a second servo band identifier of second servoband, a second pattern combination formed by the second servo bandidentifier and a third servo band identifier of a third servo band, athird pattern combination formed by the third servo band identifier anda fourth servo band identifier of a fourth servo band, a fourth patterncombination formed by the fourth servo band identifier and a fifth servoband identifier of a fifth servo band.

Data can be written to a data band via servo write heads/elements (e.g.,SW 114) or read via servo read heads/elements (e.g., SW 112) based onthe position of the at least two servo band elements of the magnetichead that is determined from among the plurality of servo bands andalong a vertical width of the magnetic tape based on the patterncombination or a comparison of the combination in a stored memory, forexample.

In other aspects, in response to the write/read operation correspondingto a different position than the determined position, the process flowcan include re-locating or adjusting the magnetic head and determininganother pattern combination with the at least two servo band elementsbeing activated to read a pair of servo bands of the plurality of servobands.

In an embodiment, in response to the another pattern combinationmatching a stored another pattern combination that is associated withthe different position, data can be written to a data band or data trackof a data band located between the pair of servo bands or a data track,wherein the determined position and the different position comprisedifferent vertical positions along a vertical width of the magnetic tapeamong the plurality of servo bands.

One of ordinary skill in the art can appreciate that the variousnon-limiting embodiments of the shared systems and methods describedherein can be implemented in connection with any computer or otherclient or server device, which can be deployed as part of a computernetwork or in a distributed computing environment, and can be connectedto any kind of data store. In this regard, the various non-limitingembodiments described herein can be implemented in any computer systemor environment having any number of memory or storage units, and anynumber of applications and processes occurring across any number ofstorage units. This includes, but is not limited to, an environment withserver computers and client computers deployed in a network environmentor a distributed computing environment, having remote or local storage.

Distributed computing provides sharing of computer resources andservices by communicative exchange among computing devices and systems.These resources and services include the exchange of information, cachestorage and disk storage for objects, such as files. These resources andservices also include the sharing of processing power across multipleprocessing units for load balancing, expansion of resources,specialization of processing, and the like. Distributed computing takesadvantage of network connectivity, allowing clients to leverage theircollective power to benefit the entire enterprise. In this regard, avariety of devices may have applications, objects or resources that mayparticipate in the shared shopping mechanisms as described for variousnon-limiting embodiments of the subject disclosure.

FIG. 6 provides a schematic diagram of an exemplary networked ordistributed computing environment that can implement one or morecomponents, devices or systems for data band identification for tapeservo devices/systems using multiple servo bands as described herein.The distributed computing environment comprises computing objects 610,626, etc. and computing objects or devices 602, 606, 610, 614, etc.,which may include programs, methods, data stores, programmable logic,etc., as represented by applications 604, 608, 612, 620, 624. It can beappreciated that computing objects 612, 626, etc. and computing objectsor devices 602, 606, 610, 614, etc. may comprise different devices, suchas personal digital assistants (PDAs), audio/video devices, mobilephones, MP3 players, personal computers, laptops, etc.

Each computing object 610, 612, etc. and computing objects or devices620, 622, 624, 626, etc. can communicate with one or more othercomputing objects 610, 612, etc. and computing objects or devices 620,622, 624, 626, etc. by way of the communications network 628, eitherdirectly or indirectly. Even though illustrated as a single element inFIG. 6, communications network 628 may comprise other computing objectsand computing devices that provide services to the system of FIG. 6,and/or may represent multiple interconnected networks, which are notshown. Each computing object 610, 626, etc. or computing object ordevice 620, 622, 624, 626, etc. can also contain an application, such asapplications 604, 608, 612, 620, 624, that might make use of an API, orother object, software, firmware and/or hardware, suitable forcommunication with or implementation of the shared shopping systemsprovided in accordance with various non-limiting embodiments of thesubject disclosure.

There are a variety of systems, components, and network configurationsthat support distributed computing environments. For example, computingsystems can be connected together by wired or wireless systems, by localnetworks or widely distributed networks. Currently, many networks arecoupled to the Internet, which provides an infrastructure for widelydistributed computing and encompasses many different networks, thoughany network infrastructure can be used for exemplary communications madeincident to the shared shopping systems as described in variousnon-limiting embodiments.

Thus, a host of network topologies and network infrastructures, such asclient/server, peer-to-peer, or hybrid architectures, can be utilized.The “client” is a member of a class or group that uses the services ofanother class or group to which it is not related. A client can be aprocess, i.e., roughly a set of instructions or tasks, that requests aservice provided by another program or process. The client processutilizes the requested service without having to “know” any workingdetails about the other program or the service itself.

In client/server architecture, particularly a networked system, a clientis usually a computer that accesses shared network resources provided byanother computer, e.g., a server. In the illustration of FIG. 6, as anon-limiting example, computing objects or devices 620, 622, 624, 626,etc. can be thought of as clients and computing objects 610, 626, etc.can be thought of as servers where computing objects 610, 626, etc.,acting as servers provide data services, such as receiving data fromclient computing objects or devices 620, 622, 624, 626, etc., storing ofdata, processing of data, transmitting data to client computing objectsor devices 620, 622, 624, 626, 628, etc., although any computer can beconsidered a client, a server, or both, depending on the circumstances.Any of these computing devices may be processing data, or requestingservices or tasks that may implicate the shared shopping techniques asdescribed herein for one or more non-limiting embodiments.

A server is typically a remote computer system accessible over a remoteor local network, such as the Internet or wireless networkinfrastructures. The client process may be active in a first computersystem, and the server process may be active in a second computersystem, communicating with one another over a communications medium,thus providing distributed functionality and allowing multiple clientsto take advantage of the information-gathering capabilities of theserver. Any software objects utilized pursuant to the techniquesdescribed herein can be provided standalone, or distributed acrossmultiple computing devices or objects.

In a network environment in which the communications network 640 or busis the Internet, for example, the computing objects 610, 626, etc. canbe Web servers with which other computing objects or devices 620, 622,624, 626, etc. communicate via any of a number of known protocols, suchas the hypertext transfer protocol (HTTP). Computing objects 610, 612,etc. acting as servers may also serve as clients, e.g., computingobjects or devices 620, 622, 624, 626, etc., as may be characteristic ofa distributed computing environment.

As used herein, the term “circuitry” can refer to, be part of, orinclude an Application Specific Integrated Circuit (ASIC), an electroniccircuit, a processor (shared, dedicated, or group), and/or memory(shared, dedicated, or group) that execute one or more software orfirmware programs, a combinational logic circuit, and/or other suitablehardware components or circuits that provide the describedfunctionality. In some embodiments, the circuitry can be implemented in,or functions associated with the circuitry can be implemented by, one ormore software or firmware modules. In some embodiments, circuitry caninclude logic, at least partially operable in hardware.

As it employed in the subject specification, the term “processor” canrefer to substantially any computing processing unit or deviceincluding, but not limited to including, single-core processors;single-processors with software multithread execution capability;multi-core processors; multi-core processors with software multithreadexecution capability; multi-core processors with hardware multithreadtechnology; parallel platforms; and parallel platforms with distributedshared memory. Additionally, a processor can refer to an integratedcircuit, an application specific integrated circuit, a digital signalprocessor, a field programmable gate array, a programmable logiccontroller, a complex programmable logic device, a discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions and/or processes describedherein. Processors can exploit nano-scale architectures such as, but notlimited to, molecular and quantum-dot based transistors, switches andgates, in order to optimize space usage or enhance performance of mobiledevices. A processor can also be implemented as a combination ofcomputing processing units.

In the subject specification, terms such as “store,” “data store,” datastorage,” “database,” and substantially any other information storagecomponent relevant to operation and functionality of a component and/orprocess, refer to “memory components,” or entities embodied in a“memory,” or components including the memory. It is noted that thememory components described herein can be either volatile memory ornonvolatile memory, or can include both volatile and nonvolatile memory.

By way of illustration, and not limitation, nonvolatile memory, forexample, can be included in a memory, non-volatile memory (see below),disk storage (see below), and memory storage (see below). Further,nonvolatile memory can be included in read only memory, programmableread only memory, electrically programmable read only memory,electrically erasable programmable read only memory, or flash memory.Volatile memory can include random access memory, which acts as externalcache memory. By way of illustration and not limitation, random accessmemory is available in many forms such as synchronous random accessmemory, dynamic random access memory, synchronous dynamic random accessmemory, double data rate synchronous dynamic random access memory,enhanced synchronous dynamic random access memory, Synchlink dynamicrandom access memory, and direct Rambus random access memory.Additionally, the disclosed memory components of systems or methodsherein are intended to include, without being limited to including,these and any other suitable types of memory.

Other examples of the various aspects/embodiments herein can includesubject matter such as a method, means for performing acts or blocks ofthe method, at least one machine-readable medium including instructionsthat, when performed by a machine cause the machine to perform acts ofthe method or of an apparatus or system for concurrent communicationusing multiple communication technologies according to embodiments andexamples described herein.

Some portions of the detailed descriptions herein are presented in termsof algorithms and symbolic representations of operations on data bitswithin a memory. These algorithmic descriptions and representations areused by those skilled in the art to convey the substance of their workto others. An algorithm, here and generally, is conceived to be asequence of operations that produce a result. The operations can includephysical manipulations of physical quantities. Usually, though notnecessarily, the physical quantities take the form of electrical ormagnetic signals capable of being stored, transferred, combined,compared, and otherwise manipulated. The physical manipulations create aconcrete, tangible, useful, real-world result.

It has proven convenient at times, principally for reasons of commonusage, to refer to these signals as bits, values, elements, symbols,characters, terms, or numbers. It should be borne in mind, however, thatthese and similar terms are to be associated with the appropriatephysical quantities and are merely convenient labels applied to thesequantities. Unless specifically stated otherwise, it is to beappreciated that throughout the description, terms including processing,computing, and determining refer to actions and processes of a computersystem, logic, processor, or similar electronic device that manipulatesand transforms data represented as physical (electronic) quantities.

The following includes definitions of selected terms employed herein.The definitions include various examples and/or forms of components thatfall within the scope of a term and that can be used for implementation.The examples are not intended to be limiting. Both singular and pluralforms of terms can be within the definitions.

“Computer-readable storage medium” or “computer-readable storage device”as used herein, refers to a non-transitory medium that storesinstructions and/or data. “Computer-readable storage medium” or“computer-readable storage device” does not refer to propagated signals,per se. A computer-readable medium can take forms, including, but notlimited to, non-volatile media, and volatile media. Non-volatile mediacan include, for example, optical disks, magnetic disks, and otherdisks. Volatile media can include, for example, semiconductor memories,dynamic memory, and other memories. Common forms of a computer-readablemedium or computer-readable storage device can include, but are notlimited to, a floppy disk, a flexible disk, a hard disk, a magnetictape, a solid state device (SSD) a shingled magnetic recording (SMR)device, other magnetic medium, an ASIC, a CD, other optical medium, aRAM, a ROM, a memory chip or card, a memory stick, and other media fromwhich a computer, a processor or other electronic device can read.

“Data store”, as used herein, refers to a physical and/or logical entitythat can store data. A data store can be, for example, a database, atable, a file, a data structure (e.g. a list, a queue, a heap, a tree) amemory, a register, or other repository. In different examples, a datastore can reside in one logical and/or physical entity and/or can bedistributed between two or more logical and/or physical entities.

An “operable connection”, or a connection by which entities are“operably connected”, is one in which signals, physical communications,or logical communications can be sent or received. An operableconnection can include a physical interface, an electrical interface, ora data interface. An operable connection can include differingcombinations of interfaces or connections sufficient to allow operablecontrol. For example, two entities can be operably connected tocommunicate signals to each other directly or through one or moreintermediate entities (e.g., processor, operating system, logic,software). Logical or physical communication channels can be used tocreate an operable connection.

“Signal”, as used herein, includes but is not limited to, electricalsignals, optical signals, analog signals, digital signals, data,computer instructions, processor instructions, messages, a bit, or a bitstream, that can be received, transmitted and/or detected.

“Software”, as used herein, includes but is not limited to, one or moreexecutable instructions that cause a computer, processor, or otherelectronic device to perform functions, actions and/or behave in adesired manner. “Software” does not refer to stored instructions beingclaimed as stored instructions per se (e.g., a program listing). Theinstructions can be embodied in various forms including routines,algorithms, modules, methods, threads, or programs including separateapplications or code from dynamically linked libraries.

“User”, as used herein, includes but is not limited to one or morepersons, software, logics, applications, processors, circuits, computersor other devices, or combinations of these.

While example methods, apparatus, and other embodiments have beenillustrated by describing examples, and while the examples have beendescribed in considerable detail, it is not the intention of theapplicants to restrict or in any way limit the scope of the appendedclaims to such detail. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the systems, methods, and other embodiments described herein.Therefore, the invention is not limited to the specific details, therepresentative apparatus, and illustrative examples shown and described.Thus, this application is intended to embrace alterations,modifications, and variations that fall within the scope of the appendedclaims.

What is claimed is:
 1. A magnetic tape comprising: a plurality of servobands comprising corresponding servo band signals to be read by servoelements of a magnetic head; and a plurality of pattern combinationscomprising servo band identifiers of the corresponding servo bandsignals from different servo bands of the plurality of servo bands;wherein a pattern combination of the plurality of pattern combinationsindicates a vertical position that is associated with the servo elementsof the magnetic head among the plurality of servo bands when performingat least one of: a write operation or a read operation to the magnetictape.
 2. The magnetic tape of claim 1, wherein the plurality of servobands comprises servo band frames that are vertically aligned withrespect to one another, and the pattern combination is formed by a firstservo band identifier and a second servo band identifier correspondingto different servo bands, respectively, and matches a stored patterncombination to receive write data of the write operation, or read dataof the read operation, at a data band of the magnetic tape.
 3. Themagnetic tape of claim 1, wherein the plurality of pattern combinationscomprises a first servo band identifier and a second servo bandidentifier of vertically adjacent servo bands that identify a locationof a data band from among different data bands to receive data by the atleast one of: the write operation or the read operation.
 4. The magnetictape of claim 1, wherein the servo elements of the magnetic tapecomprise a first servo element configured to read a first servo bandidentifier of a first servo band of the plurality of servo bands, and asecond servo element configured to read a second servo band identifierof a second servo band that is vertically adjacent, above or below, thefirst servo band.
 5. The magnetic tape of claim 1, wherein the pluralityof pattern combinations comprise a first pattern combination formed by afirst servo band identifier of a first servo band and a second servoband identifier of second servo band, and a second pattern combinationformed by a third servo band identifier of a third servo band, and thesecond servo band identifier or a fourth servo band identifier of afourth servo band.
 6. The magnetic tape of claim 1, further comprising aplurality of data bands, each located between at least two verticallyaligned and adjacent servo bands forming servo band pairs of theplurality of servo bands, and associated with a different patterncombination of the plurality of pattern combinations for positiontracking of the at least one of: the write operation or the readoperation.
 7. The magnetic tape of claim 1, wherein a patterncombination of the plurality of pattern combinations corresponds to astored pattern combination associated with a unique data band of aplurality of data bands and is read in response to activation of atleast two servo elements of the magnetic head that concurrently read afirst servo band identifier and a second servo band identifier fromdifferent servo bands for the at least one of: the write operation orthe read operation.
 8. An apparatus of a magnetic tape, comprising amagnetic head comprising a first servo element configured to read afirst servo signal from a first servo band of the magnetic tape, and asecond servo element configured to read a second servo signal from asecond servo band of the magnetic tape; a processing device, coupled tothe magnetic head, configured to determine a vertical location of themagnetic head among a plurality of servo bands along a width of themagnetic tape based on a pattern combination formed by servo bandidentifiers from the first servo signal and the second servo signal, andgenerate at least one of: a write operation, or a read operation, basedon the vertical location of the magnetic head.
 9. The apparatus of claim8, wherein the magnetic head is configured to adjust a position alongthe width of the magnetic tape from a first data band to a second databand in response to the at least one of: the write operation or the readoperation being associated with a different vertical location matching adifferent pattern combination than the pattern combination associatedwith the vertical location, or the pattern combination being associatedwith the second data band instead of the first data band.
 10. Theapparatus of claim 8, further comprising a servo write elementconfigured to write data to a data band between the first servo band andthe second servo band, or a servo read element configured to read datafrom a data band between the first servo band and the second servo band,in response to the pattern combination matching a stored patterncombination that is associated with the data band.
 11. The apparatus ofclaim 8, wherein the magnetic tape comprises different data bandsbetween different pairs of servo bands along the width and each of thedifferent data bands is associated with a different pattern combinationfor tracking positions of the magnetic head during the at least one of:the write operation or the read operation.
 12. The apparatus of claim 8,wherein the first servo band and the second servo band comprise servoframes that are vertically aligned to one another across the width ofthe magnetic tape.
 13. The apparatus of claim 8, wherein the first servoband and the second servo band comprise different servo bands withlongitudinal position (LPOS) words continuously along the magnetic tape,wherein the LPOS words each comprise a longitudinal position portionwith the servo band identifiers of the corresponding servo band signalsfor forming the pattern combination.
 14. The apparatus of claim 8,wherein the magnetic head activates the first servo element and thesecond servo element to write/read data at a location of a data bandfrom among a plurality of data bands based on whether a stored patterncombination associated with the location of the data band matches thepattern combination.
 15. A non-transitory computer-readable storagedevice storing computer-executable instructions that when executed by acomputer cause the computer to perform a method for identifying aposition of a magnetic head on a magnetic tape, the method comprising:reading, via at least two servo band elements concurrently, a pluralityof servo band signals of a plurality of servo bands that are verticallyadjacent to one another and vertically aligned along the magnetic tape;deriving servo band identifiers associated with the plurality of servoband signals that identify the plurality of servo bands; and in responseto performing at least one of: a write operation or a read operation:determining a pattern combination from among a plurality of patterncombinations based on the servo band identifiers; and determining aposition of the magnetic head among the plurality of servo bands basedon the pattern combination.
 16. The non-transitory computer-readablestorage device of claim 15, wherein the plurality of patterncombinations comprise a first pattern combination formed by a firstservo band identifier of a first servo band and a second servo bandidentifier of second servo band, a second pattern combination formed bythe second servo band identifier and a third servo band identifier of athird servo band, a third pattern combination formed by the third servoband identifier and a fourth servo band identifier of a fourth servoband, a fourth pattern combination formed by the fourth servo bandidentifier and a fifth servo band identifier of a fifth servo band. 17.The non-transitory computer-readable storage device of claim 15, themethod comprising: writing data to a data band based on the position ofthe at least two servo band elements of the magnetic head among theplurality of servo bands and along a vertical width of the magnetictape.
 18. The non-transitory computer-readable storage device of claim15, the method further comprising: in response to the at least one of:the write operation or the read operation corresponding to a differentposition than the determined position, re-locating the magnetic head anddetermining another pattern combination with the at least two servo bandelements being activated to read a pair of servo bands of the pluralityof servo bands.
 19. The non-transitory computer-readable storage deviceof claim 18, the method further comprising: in response to the anotherpattern combination matching a stored another pattern combination thatis associated with the different position, writing data to a data bandlocated between the pair of servo bands, wherein the determined positionand the different position comprise different vertical positions along avertical width of the magnetic tape among the plurality of servo bands.20. The non-transitory computer-readable storage device of claim 15,wherein the plurality of pattern combinations comprises five differentpattern combinations of at least two servo band identifiers, wherein theplurality of pattern combinations is continuous across at least twoservo bands comprising the at least two servo band identifiers along themagnetic tape and vertically aligned with respect to one another at eachservo frame.
 21. The non-transitory computer-readable storage device ofclaim 15, the method comprising: writing data to encode longitudinalposition (LPOS) information to a servo band, or reading data to decodethe LPOS information, based on the position of the at least two servoband elements of the magnetic head and a differential pulse positionmodulation operation.
 22. The non-transitory computer-readable storagedevice of claim 15, the method comprising: writing meta data into one ormore data fields to obtain a data band position; and search the one ormore data fields to detect repetitions of the meta data and determine aband position based on the meta data.